1. Field of the Invention
The present invention relates to an endoscope apparatus of an endoscope cover system for installing an endoscope into an endoscope cover expanded by an endoscope cover expander.
2. Description of the Related Art
In recent years, the endoscope apparatus has been widely employed in the medical field. The endoscope apparatus utilized in the medical sector is in some cases incapable of providing adequate viewing due to a body fluid adhered to a viewing window formed in the tip of an insert part when inserted into a living body. For this reason, an air or water supply conduit is provided for removing the body fluid adhered to the viewing window by flushing a fluid over the viewing window. Some of the endoscope apparatuses are equipped with a suction conduit for sucking and discharging the useless body fluid.
Further, some are provided with a forceps channel (treatment tool channel) whereby the tissues can be extracted by means of a living-body examining forceps, or a medical treatment can be conducted by a treatment tool.
In the endoscope apparatus provided with the conduits such as the air supply conduit or the like and the forceps channel, cleaning and antibacterial treatment are effected for surely preventing infectious diseases, etc. The complete antibacterial treatment and cleaning, however, are time-consuming. There arise problems in which a using efficiency of the endoscope decreases, and workings such as the antibacterial treatment are troublesome.
Under such circumstances, there is proposed a cover system endoscope apparatus requiring no cleaning and no antibacterial treatment by covering the endoscope itself in use with an endoscope cover to keep the endoscope itself clean.
For instance, Japanese Patent Laid-Open No. 3-29634 discloses a cover system for covering the insert part of the endoscope by inserting it into a cover (sheath). For facilitating an installation and removal of the endoscope insert part into and from the cover, the air is supplied from a cover expander into the insert part cover into which the endoscope insert part is inserted.
The insert part cover is disposable so as not to form a hole in the cover sheath due to buckling when handled in the form of a single unit or not to be ruptured when used, and is composed of a resinous tube of polyurethane for providing strength. Further, in some types of endoscope apparatuses, the insert part cover includes a channel for inserting the forceps and conduits for supplying the air and water.
Those soft resinous tubes are formed of soft materials as are possible to prevent an imbalance of flexibility in the cover endoscope inserted into the cover. The tube is, however, required to have sufficient rigidity so as to not break a cavity of the tube itself or not cause buckling. The cover as a whole has a certain degree of flexural rigidity.
That is, the insert part cover is, when the endoscope is not inserted therein, easy to break and fold. Once the cover has a tendency of being folded, this portion is repeatedly folded with the result that pin holes are formed in the cover sheath. The cover is then unusable. For enhancing the durability, the cover sheath is made resistant against folding by increasing both a thickness of the cover sheath and a hardness thereof.
The requirement of the disposable endoscope cover, however, may be a durability for one disease case. A larger thickness of the cover sheath than needed leads to a futility of costs for materials. This causes an increase in the price of the product.
Further, the enhancement of the hardness provides a high resistance against collapse but implies an easy-to-buckle state. The enhancement thereof is also apt to change the well-balanced flexibility of the endoscope according to the object and therefore worsen the insertability thereof.
By the way, the maximum bending angle of the endoscope is generally adjusted in the course of manufacturing a single unit of an endoscope. One exemplification may be a known endoscope of such a system that a plurality of bending members are connected with rivets, and a bending wire fixed to the tip part is pulled in by a near-at-hand manipulation part, thus controlling the flexure. In this case, a stopper is incorporated in a pull-in device to which the wire is connected internally of the manipulation part. The stopper is fixed in a maximum-bending-angle position while measuring a bending angle of the tip part. A maximum bending angle of the endoscope is set in this manner. Hence, when the angle is set once, the user is unable to simply alter the angle.
The endoscope with the maximum bending angle set in this way is installed into the insert part cover. When controlling the flexure, a bendable part of the endoscope undergoes a resistance of flexural rigidity of the cover described above. The bendable part cannot be therefore bent up to the maximum bending angle set in the single unit of endoscope. The maximum bending angle of the endoscope is set to an operable angle with respect to a target organ, depending on a type of the endoscope. Therefore, if the maximum bending angle required is not obtained in a state of combination of the endoscope and the insert part cover as described above, this causes a problem wherein the operability of the endoscope declines.